This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. During the reporting period we studied the process of social learning in outdoor housed groups of chimpanzees: What is the mechanism of social transmission: are apes capable of true imitation? This has been questioned by several investigators. We have been at the forefront designing tests of imitation, using "artificial fruits" (a sort of puzzle box), and finding positive results that have been widely accepted. How does behavior spread in a group? Thus far, most studies have subjected chimpanzees to human behavior to see how it spreads, but we want to know about chimp-to-chimp transmission, which is the only kind of transmission that matters in the natural habitat. We use puzzle boxes and a renovated testing facility and are in the process of imitation experiments on the chimpanzees. The unique feature of evaluating these studies, compared to all studies done before, is that the models from which the chimpanzees will learn will be conspecifics. This series of experiments matches more closely the processes of social transmission in the natural environment.